The present invention relates to a method of mending knotholes, chips, cracks and other defects which appear on the surface of a wood plate such as a veneer or a plywood.
The traditional method of mending defects of the kind described is applying putty to defective portions by use of a pallet. The use of putty, however, entails various problems because it contains water or a like solvent therein. Specifically, where wood plates mended with putty are sequentially stacked one upon another, the putty applied to the surface of the underlying plate adheres to the overlying plate because putty which contains a solvent as stated above is highly adhesive. As the plates are pulled out one by one out of the stack in the subsequent step, that part of the putty on the underlying plate which has adhered to the overlying plate is taken away by the latter and, as a result, the putty filling the defects of the underlying plate becomes short to thereby fail to sufficiently plug up the defects.
Another problem given rise to by the solvent is that in the atmosphere the solvent is allowed to vaporize to increase the viscosity and thereby change the physical property of the putty. One, therefore, has to supply a supplementary amount of solvent from time to time for maintaining adequate viscosity, resulting in troublesome maintenance. Still another problem is that as the solvent vaporizes and dries out, clearances are produced between putty and the walls of the defects due to resultant shrinkage. Should a clearance develop in an intermediate sheet of a plywood, for example, it would be visible through the nearby plates to degrade the appearance of the whole plywood.
In addition, where putty which is fluid is filled in a knothole or like defect of a veneer which extends over the whole thickness of the veneer, it flows out of the defect by gravity failing to fully plug up the defect.